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## #1 2005-12-17 04:09:50

John E. Franklin
Member
Registered: 2005-08-29
Posts: 3,588

### walk around a board

If you walk around a board laying on
the ground, you can't see its length
if you are straight in line with it.
Call this the

.
If you walk around a quarter of a
circle and look at the board
broad side, then you see the length
of the board without any shortening
like on an angle.  So call this
.  At the
slanted angles in between, it is
still the sine of the angle with the
length of the board vector.  I
thought this up because I had
a dream last night where I was
walking away from someone and
I thought to myself, they can't see
my face because of the cosine of
the angle!!  When I woke up I
tried to make sense of that!

igloo myrtilles fourmis

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## #2 2005-12-17 04:36:20

krassi_holmz
Real Member
Registered: 2005-12-02
Posts: 1,905

### Re: walk around a board

Interesting dream!

IPBLE:  Increasing Performance By Lowering Expectations.

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## #3 2005-12-17 07:05:21

mathsyperson
Moderator
Registered: 2005-06-22
Posts: 4,900

### Re: walk around a board

I think I understand. Are you saying that your eye-level is exactly the same as the level of the board, and so you see it only as a line?

If so, it the line would seem to get bigger as you walked around it and then get smaller again. If the board was rotating instead of you, it would look like some kind of phantom growy-shrinky line.

Why did the vector cross the road?
It wanted to be normal.

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## #4 2005-12-17 08:58:42

John E. Franklin
Member
Registered: 2005-08-29
Posts: 3,588

### Re: walk around a board

Yeah, that's what I meant.  I guess I should have said you look from eyes that are
on your feet, but I forgot to say that.

igloo myrtilles fourmis

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